{"id":"GHSA-3g2j-vm47-x4mj","summary":"LXD vulnerable to a local privilege escalation through custom storage volumes","details":"**Impact**\n\nThis affects any LXD user in an environment where an unprivileged user may have root access to a container with an attached custom storage volume that has the `security.shifted` property set to `true` as well as access to the host as an unprivileged user.\n\nThe most common case for this would be systems using `lxd-user` with the less privileged lxd group to provide unprivileged users with an isolated restricted access to LXD. Such users may be able to create a custom storage volume with the necessary property (depending on kernel and filesystem support) and can then write a setuid binary from within the container which can be executed as an unprivileged user on the host to gain root privileges.\n\n**Patches**\n\nPatches for this issue are available: \n\n- LXD 6 series: https://github.com/canonical/lxd/pull/16904\n- LXD 5.21 LTS series: https://github.com/canonical/lxd/pull/16922\n- LXD 5.0 LTS series: https://github.com/canonical/lxd/pull/16923\n- LXD 4.0 LTS series: https://github.com/canonical/lxd/pull/16924 \n\nThe first commit changes the permissions for any new storage pool, the later commit adds a patch that applies it on startup to all existing storage pools.\n\nThese fixes are also available in the associated candidate snap channels for each LTS series:\n\n- 5.21/candidate (5.21.4-8a3cf61)\n- 5.0/candidate (5.0.5-5c60378)\n- 4.0/candidate (4.0.10-35a8127)\n\nWe will be preparing intermediate releases to the associated stable snap channels shortly.\n\n**Workarounds**\n\nPermissions can be manually restricted until a patched version of LXD is deployed.\n\nThis is done with:\n\n```\nsudo nsenter --mount=/run/snapd/ns/lxd.mnt -- chmod 0700 /var/snap/lxd/common/lxd/storage-pools/*/{custom*,virtual-machines*,images}\nsudo nsenter --mount=/run/snapd/ns/lxd.mnt -- chmod 0711 /var/snap/lxd/common/lxd/storage-pools/*/{containers*,buckets*}\n```\n\nThose are the same permissions which will be applied by the patched LXD for both new and existing storage pools.\n\n**References**\n\nThis was reported to Incus publicly on Github here: \n\n- https://github.com/lxc/incus/security/advisories/GHSA-56mx-8g9f-5crf\n- https://github.com/lxc/incus/issues/2641","aliases":["GO-2025-4121"],"modified":"2025-11-18T18:40:12Z","published":"2025-11-13T23:01:44Z","database_specific":{"github_reviewed_at":"2025-11-13T23:01:44Z","nvd_published_at":null,"cwe_ids":["CWE-269"],"severity":"HIGH","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/canonical/lxd/security/advisories/GHSA-3g2j-vm47-x4mj"},{"type":"WEB","url":"https://github.com/lxc/incus/security/advisories/GHSA-56mx-8g9f-5crf"},{"type":"WEB","url":"https://github.com/lxc/incus/issues/2641"},{"type":"WEB","url":"https://github.com/canonical/lxd/pull/16904"},{"type":"WEB","url":"https://github.com/canonical/lxd/pull/16922"},{"type":"WEB","url":"https://github.com/canonical/lxd/pull/16923"},{"type":"WEB","url":"https://github.com/canonical/lxd/pull/16924"},{"type":"PACKAGE","url":"https://github.com/canonical/lxd"}],"affected":[{"package":{"name":"github.com/canonical/lxd","ecosystem":"Go","purl":"pkg:golang/github.com/canonical/lxd"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"0.0.0-20251110144034-698854d0164f"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2025/11/GHSA-3g2j-vm47-x4mj/GHSA-3g2j-vm47-x4mj.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}